Messages in this thread | | | Date | Thu, 03 Oct 2002 01:03:44 -0700 (PDT) | Subject | Re: virt_to_page(pci_alloc_consistent()) | From | "David S. Miller" <> |
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From: Pete Zaitcev <zaitcev@redhat.com> Date: Thu, 3 Oct 2002 02:38:14 -0400
I just noticed that sound drivers use the address from pci_alloc_consistent() as the input to virt_to_page() all over the place. I looked into the Documentation/DMA-mapping.txt, and it says:
This routine will allocate RAM for that region, so it acts similarly to __get_free_pages (but takes size instead of a page order).
I know for fact I got it wrong in sparc in whole 2.4, and it seems RMK got it wrong in arm. I suggest other architecture maintainers to look at it ASAP. May even be oopsabe, by indexing outside of mem_map[] with a suitable sound driver.
I think we MUST allow architectures to do what SPARC and ARM do, there is simply no other way to change the page protections easily for these kinds of systems.
So please instead change the DMA-mapping.txt documentation and propose pci_consistent_to_page(ptr) API additions. Next, inform the subsytems trying to use virt_to_page() on this memory that they need to use the new interface. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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